Dustin Richardson, the 26-year-old left-handed pitcher, has been suspended for 50 games, after he tested positive for five different drugs, a result that a spokesperson for Major League Baseball recognized was “unusual.”

“I’ve never seen a case like this, and we’re talking about 30 years I’ve been doing this kind of work,” said Don Catlin, an anti-doping expert and former director of the U.C.L.A. Olympic Analytical Laboratory.

“I’ve had doublets and triplets, but to have five, and have it cover three different subclasses of drugs, is unique, as far as I can tell,” Catlin added.